1. Scan and remove malware - scan for malware and remove anything that the application picked up.
2. Remove browser add-ons, extensions & toolbars
Chrome has a built-in 'Clean-up tool' which you'll find by clicking the three vertical dots and choosing Settings.
Scroll down to where it says Advanced and click on it.
Now scroll to the bottom and click 'Clean up computer' and click 'FIND' next to Find and remove harmful software.
In Firefox click the three horizontal bars near the top-right and choose Add-ons.
Now click on Extensions in the left-hand menu and click Remove next to those you want to delete.
In Microsoft Edge, click the three horizontal dots and choose Extensions from the menu.
Hover over the one you want to delete, click the cog icon then click the Uninstall button.
3. Change your home page
4. Change the default browser and remove unwanted search engines